Enable ipv6 for rootless users by default

Fixes containers/podman#10889

Inspired by @rugk

Signed-off-by: Daniel J Walsh <[email protected]>

Author: rhatdan

docs/containers.conf.5.md

@@ -433,7 +433,7 @@ and pods are visible.
 
 Path to the slirp4netns binary.
 
-**network_cmd_options**=[]
+**network_cmd_options**=["enable_ipv6=true",]
 
 Default options to pass to the slirp4netns binary.
 

pkg/config/config_test.go

@@ -165,6 +165,10 @@ var _ = Describe("Config", func() {
 				"TERM=xterm",
 			}
 
+			networkCmdOptions := []string{
+				"enable_ipv6=true",
+			}
+
 			// Then
 			gomega.Expect(err).To(gomega.BeNil())
 			gomega.Expect(defaultConfig.Engine.CgroupManager).To(gomega.Equal("systemd"))
@@ -174,6 +178,7 @@ var _ = Describe("Config", func() {
 			gomega.Expect(defaultConfig.Engine.NumLocks).To(gomega.BeEquivalentTo(2048))
 			gomega.Expect(defaultConfig.Engine.OCIRuntimes).To(gomega.Equal(OCIRuntimeMap))
 			gomega.Expect(defaultConfig.Containers.HTTPProxy).To(gomega.Equal(false))
+			gomega.Expect(defaultConfig.Engine.NetworkCmdOptions).To(gomega.BeEquivalentTo(networkCmdOptions))
 		})
 
 		It("test GetDefaultEnvEx", func() {

pkg/config/containers.conf

@@ -407,7 +407,7 @@ default_sysctls = [
 # Default options to pass to the slirp4netns binary.
 # For example "allow_host_loopback=true"
 #
-#network_cmd_options = []
+#network_cmd_options = ["enable_ipv6=true",]
 
 # Whether to use chroot instead of pivot_root in the runtime
 #

pkg/config/default.go

@@ -257,7 +257,9 @@ func defaultConfigFromMemory() (*EngineConfig, error) {
 
 	c.CgroupManager = defaultCgroupManager()
 	c.StopTimeout = uint(10)
-
+	c.NetworkCmdOptions = []string{
+		"enable_ipv6=true",
+	}
 	c.Remote = isRemote()
 	c.OCIRuntimes = map[string][]string{
 		"crun": {